Docking site interventions following bone transport using external fixation: a systematic review of the literature.

PURPOSE: Although bone transport is a well-recognised technique to address segmental bone defects, optimal management of docking sites is not absolutely determined. Some surgeons routinely intervene in all cases, and others prefer to observe and intervene only if spontaneous union does not occur. Primary aim of the study was to compare rates of docking site union between patients who underwent routine docking site intervention and those who did not. METHODS: A systematic literature review using the keywords "bone transport", "docking", "tibia", and "femur" was performed in PubMed using PRISMA guidelines. Studies published in English from January 2000 to August 2022 were included and assessed independently by two reviewers. Pooled analysis was undertaken dividing patients into two groups: those managed by routine intervention and those initially observed. RESULTS: Twenty-three clinical studies met the eligibility criteria for pooled analysis, including 1153 patients, 407 in the routine intervention and 746 in the observed group. The rate of union after initial treatment was 90% in the routine intervention group and 66% in the observed group (p < 0.0001). Overall union rates at the end of treatment were similar at 99% in both groups. Patients in the observed group required an average of 2.2 procedures to achieve union overall compared with 3.8 in the routine intervention group. Time in frame was similar between groups. CONCLUSION: Based on the current literature, routine docking site interventions cannot be recommended, since this may lead to unnecessary interventions in two thirds of patients. Timely selective intervention in those at high risk or after a defined period of observation would appear to be a logical approach.

Predictive factors for docking site procedure in bone transport for large lower extremity segmental defects.

BACKGROUND: Segmental bone transport is a common technique for treating large segmental bone defects. However, a docking site procedure is often necessary in segmental bone transport. To date, no prognostic factors for the need of docking site procedure have been reported. Thus, the decision is often made at random, based on the surgeon's subjective judgment and experience. The aim of this study was to identify prognostic factors for the need of docking site operation. METHODS: Patients with segmental bone transport in lower extremity bone defects were included regardless of age, aetiology, and defect size. We excluded patients undergoing treatments that were not yet completed, and those who discontinued therapy by any reason. The need for docking site operation was modelled with logistical and linear regression as well as univariate analysis of variances (ANOVA). Receiver operating characteristics (ROC) curve analysis was also performed. RESULTS: Twenty-seven patients from age 12 to 74 years (mean age: 39.07 ± 18.20 years) were included. The mean defect size was 76.39 ± 41.10 mm. The duration of transport (days) showed a significant influence (p = 0.049, 95%CI: 1.00-1.02) on the need for docking site operation. No other significant influences were detected. CONCLUSION: A link between the duration of transport and the need for docking site operation was detected. Our data showed that if a threshold of about 188 days is exceeded, docking surgery should be considered.

[Patient volume, diagnosis and injury mechanisms in a level 1 trauma center at the beginning of the COVID-19 pandemic in comparison to the mean of the 3 previous years : A retrospective, epidemiological evaluation of 4967 patients]. / Patientenaufkommen, Diagnosen und Verletzungsmechanismen eines überregionalen Traumazentrums mit Beginn der COVID-19-Pandemie im Vergleich zum Mittelwert der 3 Vorjahre : Eine retrospektive, epidemiologische Auswertung von 4967 Patienten.

BACKGROUND: As part of the COVID-19 pandemic, political decisions were made to reduce social interaction and to reduce the number of infections. The aim was to create capacities for the in-hospital care of the patients. OBJECTIVE: The aim of the study was to check whether a reduction in the number of trauma patients compared to the mean of the previous 3 years could be observed. MATERIAL AND METHODS: We retrospectively analyzed all patients who presented in the emergency admission from 1 March to 15 April 2020 with the mean of the patients from the previous 3 years 2017-2019. The age of the patients, time of presentation, diagnoses, whereabouts of the patients, inpatient or outpatient, number and duration of the operative care and required capacity on the normal ward and intensive care units (ICU) were recorded. The injury mechanism was also examined. RESULTS: A total of 4967 patients between 1 March and 15 April were included. On average over the 3 previous years, a total of 1348 patients, i.e. 29.3 patients per day were counted in our emergency room. In 2020 a total of 923, i.e. 20 patients per day (p < 0.01) were counted. On average 227 (24.6%) were admitted to hospital compared to 311.5 (23.1%) in 2020. On average 143 operations were performed compared to 136 in 2020. The days on the ward were reduced from 2442 on average for the previous years, in 2020 to 1172 days by 52.1% (p < 0.01). The number of days on the ICU was 450 days on average in previous years and 303 days in 2020 (-32.7%, p < 0.01). CONCLUSION: The number of patients in the emergency admission was significantly reduced in the observation period in 2020 compared to the mean of the previous 3 years. This directly made resources available for the care of COVID-19 patients.

[3D-printed template-assisted reduction of long bone fractures]. / 3D-Druck-Template-gestützte Reposition von Frakturen der langen Röhrenknochen.

INTRODUCTION: In multiply injured patients, the time period between the initial treatment with external fixators (damage control) and the definitive treatment can last from days to weeks. A poor reduction result with the fixator (e.g. malposition in axis, length and rotation) and a long delay from trauma to definitive osteosynthesis are associated with longer operation times, higher intraoperative radiation doses, higher infection rates and an increased likelihood for the necessity to perform an open reduction. MATERIAL AND METHODS: In the described technique computed tomography (CT) is performed after temporary stabilization of the long bone fracture by an external fixator. On the basis of a three-dimensional dataset the fracture can be virtually reduced and a patient-specific reduction fixator can be designed and printed. The 3D printed reduction fixator fits only in the reduced position of the fracture, thus maintaining anatomical bone alignment. The procedure was used for the first time in the Trauma Surgery Clinic of the Medical University Hanover in May 2018 in a polytraumatized female patient with severe brain injury and an open floating knee injury. RESULTS: The procedure could be performed for femoral and tibial shaft fractures. The postoperative CT showed a satisfactory reconstruction of length, torsion and frontal and sagittal plane alignment. Fracture healing was uneventful within 3 months. CONCLUSION: Severely injured patients who initially receive stabilization according to the damage control principle and subsequently remain in the intensive care unit, could particularly benefit from the described postoperative reduction technique. In addition, the reduction fixator can be helpful for the definitive treatment of patients with bilateral fractures of long bones, where a reference to a healthy side is not possible.

Fractures of the transverse processes of the fourth and fifth lumbar vertebrae in patients with pelvic ring injuries: indicator of biomechanical instability but not shock.

Aims: This study aimed to analyze the correlation between transverse process (TP) fractures of the fourth (L4) and fifth (L5) lumbar vertebrae and biomechanical and haemodynamic stability in patients with a pelvic ring injury, since previous data are inconsistent. Patients and Methods: The study is a retrospective matched-pair analysis of patients with a pelvic fracture according to the modified Tile AO Müller and the Young and Burgess classification who presented to a level 1 trauma centre between January 2005 and December 2014. Results: A total of 728 patients with pelvic ring injuries were included, of whom 183 (25.1%) had a biomechanically unstable pelvic fracture. Of these patients, 84 (45.9%) had a fracture of a TP of L4 and/or L5. A total of 73 patients (13.4%) with a stable pelvic ring injury (p < 0.001) had a fracture of a TP. Patients with a fracture of a TP of L4 and/or L5 had a 5.5-fold risk (odds ratio (OR)) of having a biomechanically unstable pelvic injury. TP fractures (OR 1.6, p = 0.2) could not be confirmed as an independent predictor of haemodynamic instability. Conclusion: This is the first study that has demonstrated a positive correlation between a TP fracture of L4 and/or L5 and a biomechanically unstable pelvic ring injury. The presence of transverse process fractures of L4 and/or L5 indicates increased severity of pelvic injury and therefore can help in the planning of emergency treatment. Cite this article: Bone Joint J 2018;100-B:1214-19.

[Proximal humeral fractures-Where do we stand today? : Comments on the "Proximal fracture of the humerus evaluation by randomization (PROFHER)" study]. / Die proximale Humerusfraktur ­ Wo stehen wir heute? : Ein Kommentar zur "Proximal fracture of the humerus evaluation by randomization (PROFHER)"-Studie.

The PROFHER study is a multicenter randomized controlled trial of 250 out of 1250 patients assessed for eligibility with dislocated proximal humeral fractures with involvement of the surgical neck. These patients were randomized either for surgery or conservative treatment. Patients with comorbidities that precluded surgery, lack of mental capacity, luxation fractures or clear indications for surgery from the authors' perspective were excluded. To evaluate the outcome, standardized self-assessment methods were used (patient reported outcome [PRO]), including the Oxford shoulder score (OSS). The results showed no differences in the primary and secondary self-assessment outcome scores after both 2 and 5 years. Although no significant differences could be detected between both groups, no clear statement could be deduced from the PROFHER study with respect to which patients would benefit from an operative treatment. Nevertheless, the PROFHER study provides a valuable and important addition to the literature on this heavily debated topic. The purpose of this review is to critically evaluate the PROFHER study within the existing literature regarding inclusion of patients, fracture treatment and evaluation of the results.

[Posttraumatic torsional deformities of the forearm : Methods of measurement and decision guidelines for correction]. / Posttraumatische Torsionsfehler am Unterarm : Messmethoden und Entscheidungsleitfaden für die Korrektur.

Forearm fractures are common in all age groups. Even if the adjacent joints are not directly involved, these fractures have an intra-articular character. One of the most common complications of these injuries is a painful limitation of the range of motion and especially of pronation and supination. This is often due to an underdiagnosed torsional deformity; however, in recent years new methods have been developed to make these torsional differences visible and quantifiable through the use of sectional imaging. The principle of measurement corresponds to that of the torsion measurement of the lower limbs. Computed tomography (CT) or magnetic resonance imaging (MRI) scans are created at defined heights. By searching for certain landmarks, torsional angles are measured in relation to a defined reference line. A new alternative is the use of 3D reformation models. The presence of a torsional deformity, especial of the radius, leads to an impairment of the pronation and supination of the forearm. In the presence of torsional deformities, radiological measurements can help to decide if an operation is needed or not. Unlike the lower limbs, there are still no uniform cut-off values as to when a correction is indicated. Decisions must be made together with the patient by taking the clinical and radiological results into account.

[Torsional malalignment of the humerus]. / Torsionsfehlstellungen am Humerus.

The torsion of the humerus describes the physiological rotation of the humerus around its longitudinal axis. Various clinical and radiological methods for measurement have been described. The computed tomography method is currently the gold standard. The angle between the humeral head axis and the transepicondylar axis is measured. This angle is called retroversion. Values of retroversion vary between 10° and 40°. For the treatment of many humeral pathologies, a precise reconstruction of the anatomical retroversion is required. The retroversion of the humerus has to be considered in shoulder arthroplasty, in fracture situations and also in planning correction of posttraumatic deformities. If an orientation to the original anatomical landmarks of the humerus is no longer possible, an orientation to the contralateral side is recommended.

[Shoulder dislocations in elderly patients]. / Schulterluxationen des älteren Patienten.

In contrast to shoulder dislocations in younger patients, anterior shoulder dislocation in the elderly is often associated with concomitant injuries to the rotator cuff and fractures. There is also frequent involvement of the brachial plexus or peripheral nerves. After closed reduction and a short period of immobilization, physiotherapy should be performed to restore mobility and strength. The evaluation of the rotator cuff is essential for further treatment decisions. The majority of patients are classically treated conservatively. Elderly patients with accompanying rotator cuff lesions and failed conservative therapy can benefit from a surgical intervention. Reconstructive interventions of the rotator cuff should be principally considered; however, some individuals may benefit from a reverse prosthesis in this elderly subgroup of patients. The challenge for the treating surgeon is to exactly define the structural injury of the shoulder (which may include pre-existing lesions) and to select the optimal treatment option.

A comparative study of negative pressure wound therapy with and without instillation of saline on wound healing.

OBJECTIVE: Negative pressure wound therapy (NPWT) has become an established treatment of traumatic and infected wounds. Negative pressure wound therapy with instillation (NPWTi) is a further development that combines the conventional NPWT with instillation of different fluids which continuously administer therapeutic reagents to the wound. The aim of this study was to compare the impact of additional saline instillation in NPWTi to NPWT alone. METHOD: Between January and July 2014, consecutive patients with acute wounds of the lower limb were treated with NPWTi with saline instillation. The number of revision surgeries, length of hospital stay, and duration of treatment until final healing were recorded and compared with matched patients undergoing NPWT without instillation. RESULTS: There were 10 patients recruited with 10 matched controls examined restrospectivley. Patients who received NPWTi were found to have decreased time of hospitalisation (21.5 versus 26.5 days, p=0.43), and accelerated wound healing (9.0 versus 12.5 days, p=0.36) than patients who received NPWT. However, the difference in the outcomes of the patients who received NPWTi and patients who received NPWT was not found to be statisticallly significant. CONCLUSION: NPWTi with instillation of saline is a promising method and its effectiveness needs to be tested in a randomised controlled trial compared with NPWT alone. DECLARATION OF INTEREST: This study obtained support by KCI (Wiebsaden, Germany) for the surgical material.

Unstable paediatric pelvic injuries: the patho-anatomical patterns of pelvic ring failure and the role of avulsion of the iliac apophysis.

Unstable pelvic injuries in young children with an immature pelvis have different modes of failure from those in adolescents and adults. We describe the pathoanatomy of unstable pelvic injuries in these children, and the incidence of associated avulsion of the iliac apophysis and fracture of the ipsilateral fifth lumbar transverse process (L5-TP). We retrospectively reviewed the medical records of 33 children with Tile types B and C pelvic injuries admitted between 2007 and 2014; their mean age was 12.6 years (2 to 18) and 12 had an immature pelvis. Those with an immature pelvis commonly sustained symphyseal injuries anteriorly with diastasis, rather than the fractures of the pubic rami seen in adolescents. Posteriorly, transsacral fractures were more commonly encountered in mature children, whereas sacroiliac dislocations and fracture-dislocations were seen in both age groups. Avulsion of the iliac apophysis was identified in eight children, all of whom had an immature pelvis with an intact ipsilateral L5-TP. Young children with an immature pelvis are more susceptible to pubic symphysis and sacroiliac diastasis, whereas bony failures are more common in adolescents. Unstable pelvic injuries in young children are commonly associated with avulsion of the iliac apophysis, particularly with displaced SI joint dislocation and an intact ipsilateral L5-TP.

Prevalence and prognostic implication of restenosis or dilatation at the aortic coarctation repair site assessed by cardiovascular MRI in adult patients late after coarctation repair.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is ideal for assessing patients with repaired aortic coarctation (CoA). Little is known on the relation between long-term complications of CoA repair as assessed by CMR and clinical outcome. We examined the prevalence of restenosis and dilatation at the repair site and the long-term outcome in patients with repaired CoA. METHODS AND RESULTS: CMR imaging and clinical data for adult CoA patients (247 patients aged 33.0 ± 12.8 years, 60% male), were analyzed. The diameter of the aorta at the repair site was measured on CMR and its ratio to the aortic diameter at the diaphragm (repair site-diaphragm ratio, RDR) was calculated. Restenosis (RDR≤70%) was present in 31% of patients (and significant in 9% [RDR<50%]), and dilatation (RDR>150%) in 13.0%. A discrete aneurysm at the repair site was observed in 9%. Restenosis was more likely after resection and end-end anastomosis, whereas dilatation after patch repair. Systemic hypertension was present in 69% of patients. Of the hypertensive patients, blood pressure (133 ± 20/73 ± 10 mm Hg) was well controlled in 93% with antihypertensive therapy. Mortality rate over a median length of 5.9 years was low (0.69% per year, 95% CI: 0.33-1.26), but significantly higher than age-matched healthy controls (standardised mortality ratio 2.86, CI 1.43-5.72, p<0.001). CONCLUSION: Restenosis or dilatation at the CoA repair site as assessed by CMR is not uncommon. Medium term survival remains good, however, albeit lower than in the general population. Life-long follow-up and optimal blood pressure control are likely to secure a good longer term outlook in these patients.

Effect of intraoperative weight-bearing simulation on the mechanical axis in total knee arthroplasty.

PURPOSE: Successful outcome after total knee arthroplasty (TKA) requires precise realignment of the mechanical axis. The intraoperative assessment of the mechanical axis is difficult. Intraoperatively, the effect of weight bearing on the lower limb mechanical axis is ignored. We developed a custom-made mechanical loading device to simulate weight-bearing conditions intraoperatively and analysed its effect on the mechanical axis during TKA. METHODS: Measurements of the mechanical axis were obtained during 30 consecutive primary TKAs in osteoarthritic patients using image-free knee navigation system. Half body weight was applied intraoperatively using our device to quantify the effect of intraoperative load application on the mechanical axis, thus receiving indirect information about soft tissue balancing. Furthermore, the intraobserver and interobserver reliability of navigated mechanical axis measurement with and without load was determined. RESULTS: Before TKA, mean mechanical axis was 4.0° ± 4.9° without load. Under loading conditions, the mean change of the mechanical axis was 2.1° ± 2.8°. Repetitive measurements of the senior surgeon and junior surgeon revealed a high intraobserver (ICC 0.997) and interobserver reliability (ICC 0.998). The registration of the mechanical axis without and with application of intraoperative loading demonstrated no significant differences during insertion of the trial components (SD 0.29 ± 0.29) and after the definitive component cementation (SD 0.63 ± 0.44). CONCLUSIONS: Intraoperative quantification and analysis of the mechanical lower limb axis applying defined axial loading by our custom-made loading apparatus is reliable. Ligament stability was unbalanced before TKA and balanced after TKA. For TKA, intraoperative simulation of weight bearing may be helpful to quantify, control and correct knee stability and its influence of mechanical axis.

[Development of compartment syndrome after intravenous administration of an X-ray contrast medium. Recommendations on acute therapy regimens]. / Kompartmentsyndrom nach paravasaler Applikation von Röntgenkontrastmittel. Empfehlung zum akuten Therapieregime.

The incidence of extravasation of contrast medium is reported in the literature to be between 0.2 % and 0.9 %. A rare consequence of this could be compartment syndrome of the affected limb which requires immediate treatment.We report the case of a patient who developed acute compartment syndrome of the forearm after intravenous injection of radiographic contrast medium in a radiovolar vein during a computed tomography (CT) scan for multiple trauma. The clinical symptoms with pain, loss of range of motion and sensitivity functions, measurement of compartment pressure and radiological images confirmed the diagnosis. After emergency dermatofasciotomy of the forearm the full range of motion and sensitivity functions could be restored.

Computer-assisted navigation of a complex femoral shaft fracture: instruction in three steps--a technical note.

The procedure of computer-assisted navigation of femoral shaft fractures is well described. Nevertheless, its use is less common. An unclear disposal and longer operation times might be two reasons. The aim of this technical note is to render assistance concerning the ideal disposal of the setup.

[Trauma sequalae after complex knee ligament injuries]. / Spätzustände nach komplexer Bandverletzung am Kniegelenk.

Complex ligament injuries can compromise a knee joint and residual conditions comprise stiffness (arthrofibrosis), instability, cartilage damage leading to osteoarthritis and bone deformity. Accurate diagnosis must address the direction and extent of the instability, the severity of any cartilage lesion and an analysis of the axis and bone deformity as well as important cofactors. Therapeutic options are adhesiolysis, ligament reconstruction, cartilage regeneration and axis correction. As a consequence patients mostly profit from the procedure but there is never a return to the functional level that existed before injury.

Influence of rupture patterns of the medial patellofemoral ligament (MPFL) on the outcome after operative treatment of traumatic patellar dislocation.

PURPOSE: Patellar dislocation usually occurs to the lateral side, leading to ruptures of the medial patellofemoral ligament (MPFL) in about 90 % of all cases. Reliable prognostic factors for the stability of the patellofemoral joint after MPFL surgery and satisfaction of the patient have not been established as yet. METHODS: This multicentric study retrospectively included 40 patients with a mean age of 22.4 ± 8.1 years (range 9-48) from 5 German Trauma Departments with first-time traumatic patellar dislocation and operative treatment. Surgery was limited to soft tissue repairs, and a preoperative magnetic resonance imaging (MRI) was performed in all cases. Evaluation of the MRI included sulcus angle, dysplasia of the trochlea, depth and facet asymmetry of the trochlea, Insall-Salvati index, Tibial tuberosity to trochlear groove (TTTG) distance, and rupture patterns of the MPFL. Patients were interrogated after 2 years about recurrent dislocation, satisfaction, and the Kujala score. RESULTS: Trochlea facet asymmetry was significantly lower in patients with redislocation (23.5 ± 18.8) than in patients without redislocation (43.1 ± 16.5, p = 0.03). Patients with a patellar-based rupture were significantly younger (19.5 ± 7.2 years) than patients without patellar-based rupture (25.4 ± 8.1 years, p < 0.02). Patients with femoral-based ruptures were significantly older (25.7 ± 9.2 years) than patients without femoral-based rupture (19.7 ± 6.1 years, p < 0.02), and had a significantly higher TTTG distance (10.2 ± 6.9 vs. 4.5 ± 5.5, p < 0.02). Patients with incomplete ruptures of the MPFL had a significantly lower Insall-Salvati index (1.2 ± 0.2 vs. 1.4 ± 0.2, p = 0.05). The Kujala score in patients with redislocations was significantly lower (81.0 ± 10.5 points) than in patients without redislocation (91.9 ± 9.2 points, p < 0.02). CONCLUSION: Younger patients more often sustain patellar-based ruptures following first-time traumatic patella dislocation, while older patients more often sustain femoral-based ruptures of the MPFL. Incomplete MPFL ruptures are correlated with lower Insall-Salvati indices. Low trochlear facet asymmetry is correlated with higher rates of redislocation. These results may be of relevance for the operative and postoperative treatment in the future. LEVEL OF EVIDENCE: Prognostic study, Level IV.

Anatomic double-bundle ACL reconstruction restricts knee extension in knees with hyperextension.

PURPOSE: Double-bundle ACL reconstruction has been demonstrated to be at least as effective as single-bundle reconstruction in terms of restoring knee rotational and translational stability. Until now, the influence on knees with hyperextension has not been evaluated. It was the purpose of this study to evaluate whether double-bundle ACL reconstruction restricts extension in hyperextendable knees. METHODS: Hamstring tendon reconstructions of 10 human cadaveric knees with the ability of hyperextension (age: 48 ± 14 years) were performed as single bundle (SB) on one side and double bundle (DB) on the other side. A surgical navigation system (BrainLab, Germany) was used to assess the kinematics of each knee at the intact and reconstructed state. A difference with regard to the anterior-to-posterior translation (AP) and rotational stability at 30° of knee flexion, 90° of flexion and the hyperextension capability of each specimen was analysed. RESULTS: The difference in AP translation before and after the reconstruction was not significantly different in 30° and 90° of flexion (n.s). Both single- and double-bundle reconstructions restored the preoperative kinematics at 30° and 90° of knee flexion (n.s). The knee extension was 4° ± 1.8° with the intact ACL and 4° ± 1.7° after reconstruction in the SB group (n.s). The knee extension was 5° of hyperextension ± 1.1° with the intact ACL and 0° ± 0.4° after reconstruction in the DB group; the limitation of the extension was significantly larger in this group (p = 0.013). CONCLUSION: Both single- and double-bundle ACL reconstruction techniques are capable of restoring knee anteroposterior and rotational stability. Double-bundle reconstructions significantly reduce knee extension in knees with hyperextension capability. Care must be taken when using double-bundle techniques in patients with knee hyperextension as this procedure may limit the knee extension after double-bundle ACL reconstruction.

[Implant-free tibial fixations of the posterior cruciate ligament. Development and biomechanical testing]. / Implantatfreie tibiale Fixierung des hinteren Kreuzbandes. Entwicklung und biomechanische Testung.

BACKGROUND: A secure tibial press fit technique in posterior cruciate ligament reconstructions may be a relevant alternative to common techniques because no hardware is necessary. Up to the present point in time no biomechanical data exist for a tibial press fit posterior cruciate ligament (PCL) reconstruction. This study compares the biomechanical properties of hamstring and quadriceps tendon grafts using a press fit technique with those of an interference screw fixation. METHODS: Quadriceps and hamstring tendons of 20 human cadavers (age 49.2±18.5 years) were used. A press fit fixation with a knot in the semitendinosus tendon (K) and a quadriceps tendon bone block graft (Q) were compared to an interference screw fixation (I) in 27 porcine tibiae. In each group, nine constructs were cyclically stretched and then loaded until failure. Maximum load to failure, stiffness and elongation during failure testing and cyclical loading were investigated. RESULTS: The maximum load to failure was 518±157 N (387-650 N) for the K group, 558±119 N (466-650 N) for the I group and 620±102 N (541-699 N) for the Q group. The stiffness was 55±27 N/mm (18-89 N/mm) for the K group, 117±62 N/mm (69-165 N/mm) for the I group and 65±21 N/mm (49-82 N/mm) for the Q group. The stiffness of the I group was significantly larger (ANOVA on ranks, P=0.01). The elongation during cyclical loading was significantly larger for all groups from the 1st to the 5th cycle compared to the elongation in between the 5th and the 20th cycle (P<0.03). CONCLUSION: All techniques exhibited larger elongation during initial loading. Load to failure and stiffness were significantly different between the fixations. The Q fixation showed equal biomechanical properties compared to a pure tendon fixation (I) with an interference screw. The results of group K were inferior. All three investigated fixation techniques exhibit comparable biomechanical properties. Preconditioning of the constructs is critical. Future randomized, clinical trials have to investigate the biological effectiveness of these fixation techniques.

Operative vs conservative treatment of traumatic patellar dislocation: results of a prospective randomized controlled clinical trial.

INTRODUCTION: Patellar dislocation is a common knee injury with mainly lateral dislocations, leading to ruptures of the medial patellofemoral ligament in most of the cases. Even though several prognostic factors for patellofemoral instability have been identified so far, the appropriate therapy for patients with patellar dislocation remains a controversial issue. The purpose of this study was to compare the outcome after conservative or operative treatment in patients after first-time patellar dislocation. PATIENTS AND METHODS: This randomized controlled clinical trial was designed multicentric including patients from six German orthopaedic and trauma departments. Twenty patients with a mean age of 24.6 years with first-time traumatic patella dislocation were included and randomized into either a conservative arm or an operative arm. Plain X-ray images of the knee joint (a.p. and lateral view and tangential view of both patellae) were performed in all cases prior to therapy to exclude osteochondral fragments requiring refixation. An MRI was recommended, but not compulsory. Patients were consulted after 6, 12, and 24 months with a questionnaire including the criteria of the Kujala score, recurrent dislocation, and satisfaction. RESULTS: The mean Kujala score of the conservative vs operative treatment group was 78.6 vs 80.3 after 6 months (p = 0.842), 79.9 vs 88.9 after 12 months (p = 0.165), and 81.3 vs 87.5 after 24 months (p = 0.339). Redislocation rate after 24 months was 37.5 % in the conservative group and 16.7 % in the operative group (p = 0.347). Due to the small number of patients that could be included, no significant difference between the groups could be detected. We see a tendency towards better results after operative treatment. CONCLUSION: Our multicentric prospective randomized controlled trial revealed no significant difference between conservative and operative treatment for patients after first-time traumatic patellar dislocation. However, a tendency towards a better Kujala score and lower redislocation rates for patients with operative treatment was observed. The small number of patients is a limiting factor of the study, leading to results without statistical significance. A meta-analysis including other study's level I data is desirable for the future.